Book I. Of the original of our ideas, their various divisions, and the manner in which they contribute to the increase of knowledge ... -- Book II. Of the grounds of human judgment, the doctrine of propositions, their use in reasoning, and division into self-evident and demonstrable -- Book III. Of reasoning and demonstration, with their application to the investigation of knowledge, and the common affairs of life -- Book IV. Of the methods of invention and science, where the several degrees of evidence are examined ..